The present invention is directed to a method and apparatus for removing injection molded plastic members from the runner, and more particularly, for removing injected molded plastic runners from a member without the use of a knife.
Injection molding of plastic products has become one of the most common and popular ways for making plastic pieces such as forks, spoons, toys, or the like. In mass production, a single mold may produce dozens of individual pieces.
As shown in FIG. 1, it is conventional for the mold to produce a unitary plastic array 10. Array 10 includes a runner 12 extending the length of unitary array 10. Along runner 12 are attached the members 14 which will become the end product. By way of example, as shown, members 14 could be forks. Each member 14 is connected to runner 12 by a gate 16. For packaging and sale, members 14 are separated from runner 12.
It is known in the art to separate, or degate, members 14 from runner 12 utilizing a knife or cutting edge. This has been satisfactory, however, as the knife cuts the gate, it leaves vestige (a portion of gate 16) on the now separated fork 14. Often, the cut is inaccurate and at an angle, so that the vestige provides a slanted or sharp edge which can catch on the packaging or the skin of the end user of the finished product. Furthermore, because all of the pieces are made of plastic, the now degated runners can usually be recycled. Therefore, the cleaner the cut and the more of gate 16 which remains on runner 12 after degating the more efficient the recycling process.
Accordingly, it is desired to provide an improved degating method and apparatus.
A degating apparatus includes a first support platform for supporting the members affixed along one side of a runner and a second platform disposed adjacent the first platform for supporting the members affixed to the opposite side of the runner. The first platform and second platform are disposed in a first position in which the first plate is coplanar with the second plate along a pivot axis. The first platform pivots about the pivot axis through a positive angle relative to the first position to a first position and through a negative angle relative to the first position to a second position. The second platform also pivots about the pivot axis through a positive angle about the pivot axis to a second position and through a negative angle relative to the first position to a third position. In a preferred embodiment, the positive angle and negative angle are each at least 30 degrees from the first position.
Additionally, in a preferred embodiment, hold-down members are provided to maintain the plastic members against the respective platforms during movement between positions and to hold the runner in place during movement between positions.
During use, the unitary molded piece is placed on the first platform and second platform so that the platforms are in the first position, the runner is disposed between the platforms, and a first plurality of members extending from one side of the runner rest on the first platform and a plurality of runners extending from the opposite side of the runner rest on the second platform. The runner is held in position to remain in the plane of the first position while the platforms are rotated to the respective second positions and then to the respective third positions. The members are then removed from the first and second platforms.
Accordingly, an object of the invention is to provide an improved method and apparatus for degating.
Yet another object of the invention is to provide a method of degating which reduces the amount of vestige.
Yet another object of the invention is to increase the recycling efficiency of the injection molding process.
Still other objects of the invention will, in part be obvious, and will, in part, be apparent from the specification.
The invention accordingly comprises the several steps and the relation of one or more of such steps with respect to each of the others, and the apparatus embodying features of construction, combination(s) of elements and arrangement of parts which are adapted to effect such steps, all as exemplified in the following detailed disclosure, and the scope of the invention will be indicated in the claims.